How would you like the list, and how often would you need it?

One way would be to just hook up on an event when a new page is created, and add the page to your list. See this post on how to hook up to the event.

If you need all pages it will be slower, but you could use IContentRepository.GetItems with your wanted language and check which ones were returned with the fallback master language. See this code for getting pages with a fallback and filtering it.